What Is The Raw Material Of Pu Foam
1. Main raw materials
(1) Isocyanate is the core component of the reaction, forming a polyurethane chain with polyols and producing CO₂ gas (foaming source). Common types include diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), etc.
(2) Polyol reacts with isocyanate to form a polymer skeleton, and its molecular weight and functionality affect the softness and hardness of the foam. Types include polyether polyol (commonly used for soft foam) or polyester polyol (commonly used for hard foam).
2. Auxiliary raw materials
(1) Blowing agents are mainly divided into physical blowing agents such as HFCs (hydrofluorocarbons), water (reacts with isocyanates to produce CO₂), liquid CO₂ and chemical blowing agents. Water is the most commonly used, releasing CO₂ gas through the reaction.
(2) Catalysts are mainly divided into amine catalysts (such as triethylenediamine) to accelerate the reaction between isocyanate and water (foaming) and metal catalysts (such as stannous octoate) to promote the reaction between isocyanate and polyol (gelling).
In summary, soft PU foam (such as sofa cushions and mattresses) often uses TDI and highly reactive polyether polyols, with high water content and physical blowing agents. In contrast, rigid PU foam (such as insulation) often uses MDI and high-functionality polyester polyols, with low water content and reliance on physical blowing agents (such as cyclopentane).
